The present disclosure relates to systems and methods for assessing and tracking cardiovascular fitness. More particularly, the disclosure relates to systems and methods for assessing and tracking cardiovascular fitness using a noninvasive measure of overall cardiovascular fitness and athletic performance.
The field of physical fitness assessment and testing has seen an increasing demand with rising public interest in physical fitness and the relevance of performance to soldiers, firefighters, athletes, and the like. For instance, with the high demand and financial stakes of professional and collegiate athletics, there is strong interest in accurately testing and predicting the physical fitness of the athletes. In addition, the increasingly health-conscious public is interested in assessing physical fitness for personal knowledge. However, conventional vital signs measured by current fitness devices are often inaccurate and poor predictors of cardiovascular fitness in healthy persons.
Thus, health clubs and physiological laboratories now conduct elaborate fitness and performance assessments. Such assessments often test the aerobic and anaerobic fitness of participants. Several different tests have been used to make such aerobic and anaerobic assessments. However, drawbacks of the typical anaerobic and aerobic tests include the length of time and expense involved. For instance, aerobic tests typically require from five to twenty minutes of strenuous exercise. Further drawbacks include the use of sophisticated equipment. Additional drawbacks include, for instance, anaerobic fitness being limited to a power output of a stationary bicycle and not a power output of an individual being tested.
A common laboratory test to predict cardiovascular fitness includes the assessment of maximal oxygen uptake or consumption (VO2max). VO2max is the maximal capacity of an individual to perform aerobic work. VO2max is the product of cardiac output (CO) and arteriovenous oxygen (a-vO2) difference at exhaustion, and the golden standard measure for a person's aerobic fitness. The assessment of a person's VO2max indicates the maximal amount of oxygen the individual can utilize typically over one minute during an intense, maximal physical effort. Aerobic fitness is related to a person's ability to perform dynamic, moderate-to-high intensity physical activity with large muscle groups for prolonged periods. Thus, VO2max expresses the abilities of both cardiorespiratory and muscular systems to transport and utilize oxygen for energy.
Typically VO2max is measured directly by analyzing inspired and expired breathing gases in a laboratory setting during maximal exertion, and expressed either as absolute maximal amount of oxygen per minute (L/min) or as relative to the individual's weight as the maximal milliliters of oxygen the person uses in one minute per kilogram of body weight (ml/kg/min). Individual VO2max values can range from about 10 ml/kg/min in cardiac patients to close to 90 ml/kg/min among world-class endurance athletes. Average values for men and women in different age groups have been used to establish reference fitness categories, as aerobic fitness generally declines with age.
However, as described above, measuring a person's VO2max must be done in a laboratory setting. In addition, laboratory tests require expensive equipment and trained personnel, and are thus difficult and expensive to perform. Therefore, these tests are not feasible for large-scale use and do not allow for frequent follow-up of aerobic fitness.
Thus, it would be beneficial to have systems and methods to measure accurate, real-time cardiovascular fitness information from individuals, without the need for a laboratory setting. Accurate and readily available information could be used, for example, to assess the current fitness level in different populations, motivating towards physical activity, giving feedback on specific exercise sessions or long-term progress, helping to choose suitable exercise modes, and even in planning entire training programs.